Method of applying hardened gripping areas to the spring clip of a shuttle



July 7, 1970 w. c. GUSTAFSON 3,5 ,0

METHOD OF APPLYING HARDENED GRIPPING AREAS 1'0 THE SPRING CLIP OF A SHUTTLE Filed June 28, 1968 MZZeP'G'. Ga sza/dorz United States Patent US. Cl. 139-207 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to the application of long wearing surfaces including tungsten carbide in powdered form applied to desired locations on a spring clip for bobbins by spraying under conditions of heat and including a minor percentage of a suitable bonding agent, e.g. powdered cobalt.

BACKGROUND OF INVENTION This invention resulted from an effort to improve the spring clip for bobbins disclosed in US. Pat. No. 3,259,150, July 5, 1966, in which the conventional spring clip or grip for holding bobbins in loom shuttles was improved by the insertion in certain desired locations of hard metal inserts, and brazing the inserts in position so that the patented shuttle spring clip was much longer lasting than those of the prior art. It was found that although the spring clip and method of altering the same as disclosed in said patent above identified is very satisfactory, it is, however, relatively expensive to manufacture and this invention provides a way of obtaining an equivalent spring clip by a much less expensive operation.

SUMMARY OF THE INVENTION The spring clip for bobbins has a pair of cooperating spring arms which. are grooved transversely with respect to the lengths thereof forming grooves or depressions for each bobbin head ring, these rings being received in the grooves or depressions which form gripping points for each ring by which the bobbin head is clamped.

At these gripping points at least, a finely powdered hard material, e.g. tungsten carbide is sprayed at a relatively high heat (approximately 2800 C.) and becomes bonded with the material of the spring clip which is, e.g. steel. This provides the clips at the requisite points with an extremely hard long wearing lamination and in effect, such a spring clip will last almost as long as a spring clip made according to US. Pat. 3,259,150. It has been found that by mixing a small percentage, e.g. 20% of powdered cobalt with the powdered tungsten carbide, the bond made is enhanced and one of the advantages of this invention is that even though a high heat is used in the process, the resiliency of the spring clip is not affected, and in addition, the costs of forming cuts or openings, introducing hard inserts, and then brazing, are avoided.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention, however may be best understood by reference to one of its structural forms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a view in elevation illustrating a bobbin held by a spring clip;

FIG. 2 is an enlarged view in side elevation of the spring clip;

3 ,5 19,031 Patented July 7,, 1970 FIG. 3 is an enlarged section on line 3--3 of FIG. 1;

FIG. 4 is a view in elevation of the reverse side of the spring clip arm of FIG. 2, broken away; and

FIG. 5 is a section on line 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION In order to explain the present invention, the bobbin has been illustrated at 10 and its steel rings at 12, there usually being three of these rings on the head portion 14 of the bobbin. The spring clip is generally shown by the reference character 16. This clip is generally shaped more or less as shown and has a pair of spring arms 18 and 20 connected at the narrow or closed end 22 of the clip and connected to the shuttle as usual by a metallic clip 24.

The spring clip is provided with indentations like grooves or depressions as at 28 and these appear at the inside aspects of the arms 18 and 20. There is a groove or depression 28 in each spring arm for each bobbin head ring 12, these rings being received in the grooves as shown in FIG. 1.

This construction provides two spaced gripping points for each ridge between the grooves as indicated at 30, 30, providing three sets of four spaced gripping points for the head, although usually the center pairs are arranged so as not to grip until the others wear to some extent. In time, the spring clips wear to such a degree that the bobbin s no longer gripped, and the clip must be thrown away.

In the present invention, these gripping areas are provided with hard, long wearing surfaces preferably including tungsten carbide or some similar hard material, e.g., to provide for extra long wear of the parts. In order to do this, the tip ends of the arms of the spring clip are sprayed with tungsten carbide in powder form or with some other similar powdered material at a heat of approximately 2800" C. or thereabout, it being discovered that spraying the hard powdered material under pressure and at this heat or thereabouts causes the long wearing powdered material to closely adhere or bond to the surfaces against which it impinges. forming a practically indestructable hard and long wearing surface at the desired points.

As a minor aspect of the invention, the points to be processed may be applied by masking the remainder of the end of the spring clip or the entire end of the spring clip may be substantially covered by the hardened material. In any event, the areas at 30, 30, are necessarily so treated.

It will be seen therefore that a relatively small amount of tungsten carbide or similar material is used compared to the insert method employed in US. Pat. 3,259,150, and also it will be appreciated that it is less expensive to spray the material than it is to provide inserts for prepared openings as disclosed in the aforesaid patent.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. The method of providing a. shuttle spring clip for holding a bobbin, including a pair of spaced arms between which the bobbin is to be gripped, the arms having a conformation for the reception of said bobbin, including the steps of spraying the gripping areas only with powdered tungsten carbide providing a layer of harder References Cited longer Wearing material at the gripping areas.

2. The method of claim 1 wherein the tungsten carbide UNITED STATES PATENTS is applied at a heat of approximately 2800 C. 2,674,542 4/1954 Alexander 117-131 X 3. The method of claim 1 wherein the tungsten carbide 5 3,101,274 8/1963 Beyerstedt et 117131 X is applied at a heat of approximately 2800 C. and in- 3259150 Gustafson 139-207 cludes a relatively small percentage of a bonding agent. 3,378,044 4/1968 Boggs 139-407 4. The method of claim 1 wherein the tungsten carbide FOREIGN PATENTS 1s applled at a heat of approx1mately 2800 C. and m- 1,078,876 8/1967 Great Britain.

cludes a relatively small percentage of a bonding agent 10 mcludmg PQWdered mbak- JAMES KEE CHI, Primary Examiner 

